Method and system for fabricating object featuring properties of a hard tissue

Abstract

A method of additive manufacturing an object featuring properties of a hard bodily tissue, comprises: dispensing and solidifying a plurality of non-biological material formulations to sequentially form a plurality of hardened layers in a configured pattern corresponding to a shape of the object. The method forms voxel elements containing different material formulations at interlaced locations to provide a three-dimensional textured region spanning over the portion. The material formulations and the interlaced locations are selected such that the textured region exhibits, once hardened, a stress variation of at most ±20% over a strain range of from about 0.1% to about 0.3%.

What is claimed is: 
     
       1. A method of additive manufacturing an object featuring properties of a hard bodily tissue, the method comprising:
 dispensing and solidifying a plurality of non-biological material formulations to sequentially form a plurality of hardened layers in a configured pattern corresponding to a shape of the object, wherein for at least a portion of said layers, wherein said dispensing comprises: 
 forming voxel elements containing different material formulations at interlaced locations to form a three-dimensional textured region spanning over said portion and comprising a plurality of texture elements each comprising an interior portion surrounded by a wall portion, wherein said interior and said wall portions are made of different material formulations and wherein said material formulations and said interlaced locations are selected such that said textured region exhibits, once hardened, a stress variation of at most ±20% over a strain range of from about 0.1% to about 0.3%; and 
 dispensing at least one of said material formulations to form a shell at least partially surrounding said textured region. 
 
     
     
       2. The method of  claim 1 , wherein said interlaced locations are selected according to a modulating function. 
     
     
       3. The method of  claim 2 , wherein said modulating function comprises a noise function. 
     
     
       4. The method of  claim 3 , wherein said modulating function comprises a simplex noise function. 
     
     
       5. The method of  claim 3 , wherein said modulating function comprises an open simplex noise function. 
     
     
       6. The method according to  claim 3 , wherein said function comprises a Worley noise function. 
     
     
       7. The method according to  claim 3 , wherein said function comprises a Perlin noise function. 
     
     
       8. The method according to  claim 3 , wherein said function comprises a wavelet noise function. 
     
     
       9. The method according to  claim 2 , wherein said modulating function comprises a periodic function. 
     
     
       10. The method according to  claim 9 , wherein said modulating function has a period of 2 or less millimeters. 
     
     
       11. The method according to  claim 2 , wherein said modulating function comprises an aperiodic function. 
     
     
       12. The method according to  claim 1 , wherein said material formulations comprise a first material formulation which provides, upon said solidifying, a first material, and a second material formulation which provides, upon said solidifying, a second material, and wherein said interior portion is made of said second material and said wall portion is made of said first material. 
     
     
       13. The method according to  claim 12 , wherein said wall portion is harder than said interior portion. 
     
     
       14. The method according to  claim 1 , wherein said material formulations comprise a first material formulation which provides, upon said solidifying, a material having a tensile strength of from about 40 to about 60 MPa according to ASTM D-638-03 and a modulus of elasticity of from about 1000 MPa to about 2600 MPa according to ASTM D-638-04, and a second material formulation which provides, upon said solidifying, a material having a modulus of elasticity of from about 10 kPa to about 100 kPa according to ASTM D-575. 
     
     
       15. The method according to  claim 1 , wherein said material formulations comprise a first material formulation which provides, upon said solidifying, a material having a tensile strength of from about 40 to about 60 MPa according to ASTM D-638-03 and a modulus of elasticity of from about 1000 MPa to about 2600 MPa according to ASTM D-638-04, and a second material formulation which provides, upon said solidifying, a material selected from the group consisting of(i) a material having a modulus of elasticity of from about 10 kPa to about 100 kPa or from about 10 kPa to about 50 kPa according to ASTM D-575; (ii) a material having a modulus of elasticity of from about 0.1 MPa to about 1 MPa according to ASTM D-575; and (iii) a material featuring a Shore A hardness lower than 10 or a Shore 00 hardness lower than 30. 
     
     
       16. The method according to  claim 15 , wherein said material formulations comprise a third material formulation featuring at least one of:
 a viscosity of no more than 10000 centipoises; 
 Shear loss modulus to Shear storage modulus ratio greater than 1; 
 a Shear modulus lower than 20 kPa; flowability when subjected to a positive pressure of no more than 1 bar; 
 a shear-thinning and/or thixotropic behavior; and 
 a thermal-thinning behavior. 
 
     
     
       17. The method according to  claim 1 , wherein a hardness of said shell once hardened is higher than a hardness of said textured region once hardened. 
     
     
       18. The method according to  claim 17 , wherein said dispensing comprises dispensing at least one of said material formulations to form a flexible annulus structure in said shell, wherein an interior of said annulus structure is made of the same material formulation or material formulations as said shell. 
     
     
       19. The method according to  claim 17 , wherein said dispensing comprises dispensing at least one of said material formulations to form on said shell a structure having a shape of a soft tissue element. 
     
     
       20. The method according to  claim 17 , wherein said dispensing comprises dispensing at least one of said material formulations to form a coating over said shell, such that once said textured region, said shell, and said coating are hardened, a hardness of said coating is higher than a hardness of said shell. 
     
     
       21. The method according to  claim 20 , wherein said dispensing comprises dispensing at least one of said material formulations to form on said coating a structure having a shape of a soft tissue element. 
     
     
       22. The method according to  claim 17 , wherein said dispensing comprises dispensing at least one of said material formulations to form a core surrounded by said textured region and/or said shell, such that once said textured region and said core are hardened, a hardness of said textured region is higher than a hardness of said core. 
     
     
       23. The method according to  claim 1 , wherein said dispensing comprises dispensing at least one of said material formulations to form a section having a shape of a bone tumor, and having mechanical properties that differ from mechanical properties of any voxel adjacent to said section outside said section. 
     
     
       24. An object made of a plurality of non-biological materials and being fabricatable by the method according to  claim 1 .